Propeller pitch adjusting device



March 21, 1950 BQQTH 2,501,432

PROPELLER PITCH ADJUSTING DEVICE Filed Dec. 18, 1944 4 Sheets-Sheet 1 upZNVENZUE James H B 00th March 21, 1950 J. H. BOOTH 2,501,432

PROPELLER PITCH ADJUSTING DEVICE Filed Dec. 18, 1944 4 Sheets-Sheet 2Jame; H1300 Zfh ZZ/WWW Mangh 2N1 }950 J. H. BOOTH 2,501,432

PROPELLER PITCH 'ADJUSTING DEVICE Filed Dec. 18, 1944 4 Sheets-Sheet-4Patented Mar. 21, 1950 PROPELLER PITCH ADJUSTING DEVICE.

James H. Booth, Detroit, Mich., assignor to Thompson Products, Inc.,Cleveland, Ohio, a

corporation of Ohio Application December 18, 1944, Serial No. 568,605

2 Claims.

This invention relates to an inexpensive device for adjusting members,such as blades, and specifically relates to an easily installedpropeller pitch adjusting device.

The invention provides a small compact assembly, rotatable with apropeller hub, for changing the pitch of propeller blades that arerotatably mounted in the hub. The assembly includes fluidpressure-operated means acting on the blades to rotate them in theirmountings. Fluid pressure for actuating these means is created by apump. The pump is actuated by a non-rotatable cam, and this cam ismanually actuated by the pilot into and out of pump-operating position.i

According to this invention, the blades of a propeller are mounted forrotation in a propeller hub in such a manner that the aerodynamic forceon the blades in operation tends to move them into high pitch. Thedevice of this invention is contained in the hub of the propeller and,when the cam is moved into position for actuating the pump of the devicewhich rotates with the propeller hub, the hydraulic pressure generatedby the pump will move the blades into low pitch against thisaero-dynamic force.

In order to cause the aero-dynamic forces on the operating blades tourge the blades into high pitch, the blades are tilted back from theirradial rotating axes to move their centers of gravity toward theircenters of radial rotation to lessen or negative the centrifugal torsioneiiect tending to rotate the blade into low pitch and the blades aredesigned to have their centers of pressure to the front of the centersof radial rotation.

While aero-dynamic force alone can be relied upon to urge the bladesinto high pitch, it should be understood that this force can beaugmented by springs, weights, or the like.

A feature of this invention resides in the provision of a compacthydraulic pressure-operated propeller pitch-changing device that can bereadily installed on standard airplane engine mountings.

Another feature of the invention resides in the provision of aself-contained unit in a propeller hub for changing the pitchof bladesrotatably mounted in the hub.

Another object of this invention is to provide a hydraulically-operatedpropeller pitch changer utilizing only minute quantities of oil or otherhydraulic fluid.

v A further object of the invention is to provide a device which adjuststhe positions of rotating blades in accordance with the manuallyadjusted position of a non-rotatable member.

A still further object of the invention is to provide a propellerpitch-adjusting device wherein a stationary cam actuates a pump forproducing pressure to change the pitch of propeller blades.

A still further object of the invention is to provide a propellerpitch-changing device embodying a cam member actuated into and out ofoperating position by the pilot of the plane and, when in operatingposition, causing a pump rotatable with the propeller to producehydraulic pressures for overcoming aero-dynamic forces on the propellerblades to change the pitch of the blades.

Another object of this invention is to provide a propellerpitch-changing device having a pump actuated by a cam and a fluid flowcontrol valve actuated by another cam to operate plungers for movingpropeller blades about their radial axes.

Other and further objects of the invention will be apparent to thoseskilled in the art from the following detailed description of theannexed sheets of drawings which, by way of preferred example,illustrates one embodiment of the invention.

On the drawings:

Figure l is a plan view of a propeller mounting according to thisinvention embodying a propeller pitch changing device according to thisinvention.

Figure 2 is a front end elevational view of the mounting shown in Figure1 with parts of the propeller blades omitted.

Figure 3 is a cross-sectional view taken along the line III-III ofFigure 1.

Figure 4 is a cross-sectional view taken along the line IV--IV of Figure1.

Figure 5 is a cross-sectional view taken along the line V-V of Figure 2.

Figure 6 is a cross-sectional view taken along the line VI-VI of Figure5.

Figure '7 is a cross-sectional view taken along the line VII-VII ofFigure 4.

Figure 8 is a plan view taken along the line VIII-VIII of Figure 7.

Figure 9 is a cross-sectional view taken along the line IX-IX of Figure8.

Figure 10 is a cross-sectional view taken along the line XX of Figure 8.

Figure 11 is a cross-sectional view taken along the line XIXI of Figure8.

Figure 12 is a fragmentary crosssectional view taken along the lineXIIXII of Figure 13.

Figure 13 is a plan view of the ring block taken along the lineXIII-XIII of Figure 5.

Figure 14 is a plan view of the cover plate for the ring block takenalong the line XIV-XIV of Figure 5.

Figure 15 is a developed diagrammatic view illustrating the operation ofthe fluid pressure actuated parts of the device of this invention.

As shown on the drawings:

As best shown in Figures 1 and 5, the device of this invention includesa mounting plate II] for operatively attaching certain parts of thedevice to an airplane engine I I. The engine H has upper and lower bossportions Ha. Brackets l2,

I 82 carried by the mounting plate It straddle each boss portion lid anda connecting pin or lug l3 secures the brackets to the bosses.The'ni'ount ing plate I!) has a cylindrical collar portion illprojecting forwardly from the front end of the engine ll and this collarportion vIlla slidably receives a control member Mhaving a cylindricalside wall in engagement with the -collar portion Illa and equipped withseveral sloping slots H5 at spaced intervals therearound as best shownin Figures 3 and 7. These slotsv 15 receive theheads 16a of bolts 16which are passed through thickened portions of the collar Illa andsecured to the collar by means of nuts I! as best shown in Figure .3. r

The collar lll'a-h'as an elongated slot lob there" in and an arm 'l-Bsecured on the control member l4 extends through the "slot lilb toreceive a clevis l9 on the end of a control rod, an operating Bowdenwire or the like 20. The control rod 2t passes through an aperture inthe mounting plate lilo, as'shown in FigureS, and is directed tothe'cock'pit or the airplane where it cah'be easily reached for manualactuation by the pilot. Movemerit of 'the control rod!!! will swing thearm 18 to rotate the control member i l in the collar portion lfld.However, since the heads ltd proj'ect into the ungousisiot ihof thecontrol member 14, any ro'tati'onfoi the "control member will slide itaxially relative to'jth'e collar the.

mounted about longitudinal or radialaxes such 'of the blades; Asexplained above, each blade is 7 so tilted with respect to its axis ofradial rotation The control member an'end face with 'a cam track Hidtliereo'n'ali'd "a flat surface Mb surrounding the cam track Ma.

As shown in Figures 1, 5 aridj'ka propeller hub casing 2i ha'sfa rearend portion freelye'mbracare the sonar portion i-toot the i nounting ila"te ill. This casing 21 has 'dialhetri'cally opposed laterallyprojecting cylindrical socket or sleeve portions f2la which receive theinner ends ofpropeller'blades B. V p

The hub casing 2!, as best shown in Figure 5 has a back wall 2'! b's'paeedin' front of the'i'nountingplate H] and extending radiallyinward'tjo a central hoss Or hub portion zicjwhi h is mounted on theengine shaft S; proi from the front end ofengin'e ii. The ehgl-n'e shafts is prererably tapered to receive th'e'hub portion 'fiic in Wedgin'gr'elatioh'shib ahd keyiheahs 'suchfas K (Figure 4) connect the'shaft'and hub portion tic for corotat'ion.

A nut 22 is threaded the front nd offl ne shaft'S tothrust'a'gainstthetno of the "portion Ho and hold it on the shaft.Thisnut is locked ag'a'ihst rotation by means ofjpins such as anchoredin the nut and "hollow'skirt-like end S of the shaft.

A streamlined nose casing 24 is secured onfthe front end or thehub'casing 2Tby means of screws 25 or the like for coveiihg'th'e openfront of the S 'Z- A s o. I v t The blades 13 have their inner endssecured'in tapered "skirt portions 25 6a or retaiiier members 26 whichare rotatably mounted on ball bearings"?! in the'soeket no or thehub'c'as'i'ng. Nutses threadedbn the socket's il a thrust against theouter race rings of the ballbearings 2'1 to retain these outerraceriires in the socket. The ball 'df the bearings retain the i'nlfle'rrace rings in position all'd a 'lo'ckihg' ring 29 retained in groove ofthe retaine'r'h-l'e'inberlfi thrusts against an inner-race ring of oneof the bearing assem- 'lo lie's so that the retainer cannot move axiallyrelative to the socket tidy However, the retainer can rotate freelylwiththefinner race rings 'of the ball bearings 2i. Theblades'B"are'thusrotatably A to negative centrifugal torsion effecttending to rotate the blade into low pitch and has the center P ofpressure on the blade forwardly from this axis A so that aerodynamicforces on the blade tend to rotate it into high pitch.

The retainers "26 for the blades B have tail por- MODSZBUBXtlldiYlgilltOthe casing 2i. These tail portions 261) carry laterally projecting pins30 and '3! in ri'ght'angular relation. The pins 3i project into slotsZld ofthe rear Wall 25b of the hub casihg'N, as nest'snow'n in Fi'gures'l and '5. Set screws 32 are threaded into the Wall 2 to to project intoopposite sides of theslots "21d and ror m abutments for the pins 31thereby limitin the a'nio'u'ntof rotation of the blades 13 about theaxes of radial rotation A. Thesesetfscrews 32 can be "adjusted sothat'the'amo'uiit or radial rotation of the blade "can be controlled toany desired 'degre'e. Likewise the screws can be adiusteuso that thedesired high pitch and low pitch p'o'sitions for the blades canbeobtain'e'dsince the setting "of screws 321on one side of the pins 3|will determine the high pitch positions forthe blades '33 while thesetting of scre'ws on the other side of the pins 3i will determi'iiethelow pitch positions 'fortheblade's. 'lruesirdsprings (notshow'h) can beus'edto act "on the pins} for'urging the blades to rotate into highpitch positions, thereby assisting'thefareodyriarnic force'Which'lnaintairls theblades high pitch positions. 7

Nuts '33 can be provided on the set screws 32 for locking the sameinadjusteu position. I s

As best shown in Figure5,'a ring block 3 5 mounted in the hubba'Sing'Z'Iand has'ac'entral aperture 35a extending ro'i n one end face thereor toreceive the endo'f "the hub'portion'2lc. A shoulder 35b is provided atthe bottom or the aperture 35a to thrust against the end'of the hubportion 2 In. A'second aperture-tee extends inwardly from the otherend'of thefringblock 35 to receive the nut '22 freely therein and thisaperture 35c has a Shoulder 35d at the bottom thereof bottoming a flange22aof the nut. The ring block 35 is thus securedftothehlib 21c.Inadditioh, however, bolts suc as '36 are passed through the ring blockand threaded into the back wall'2lb of the'hub 21-. I g

A top cover plate '31 held on "the ring'block by means 'ofcap screwssuch as 38threaded into or v the block. a bo'ttomc'over'39 is held ontheb'ottom'or the'ring block by means o'f"boltsblichas As best shown inFigure 12, the ring bl'ock' 35 carries anoil't'ankor casing '41inYanaperture thereof, and this 'ca'sing "4i lprojec'ts 'beyond" thebottom cover '39 intoth'e sp'acebe'tween the bottom cover and the endwall 21b "of the hub2l. A plunger "42 is 'sl'id'ably mounted in thcasing 4| and this plunger flfz has a head H'Zaat'oiie'end thereofslidably engagihgthe walls ofi'the casing, together with a reduceddiameterhollow shank portion 42b projecting towardth-e other e'nd of thecasing in spacedfrela'tioninward from the casii'rg wall. "The headf42'aghas vents E3 erethrough connecting th esp'aceiin' the tankb'etw'eh the'liead and end 'wall'of the' tahkwith the space in tr e'tasurrounding the sh nk :211. -A"fsea'1 44 s "carried by thesharia-42oandjslidabiy e gages 'thewa'll of t tam; infs'ealin'g relationtherewith. 'A "Coil "Spring 45is Contained"ih"the shank 42b to urge theplunger 42 toward the closed end of the tank. A plug 46 is threaded intoaisle cover plate 31 for bottoming the coil spring Oil or otherhydraulic fluid in the tank 4| is thus always maintained under springpressure, so that air can never be delivered to the system in the eventof leakage of oil. For example, as oil might leak out of the system, orcontract due to temperature changes, the spring 45 will urge the plungermember 42 down toward the closed bottom of the tank for decreasing thesize of the tank, since the seal 44 will render ineffective any portionof the tank interior lying between it and the open end of the tank. Theoil is vented from the closed end portion of the tank through the holes43 into the space surrounding the shank portion 42b of the plunger fromwhch the oil is fed into the system.

When it is desired to fill the system with oil or other operating fluid,the plug 46 and spring 45 are removed, a rod is threaded into thethreaded well portion of the plunger, and the plunger is retractedtoward the cover plate 31. Both plugs shown in Figure 15 are removedfrom the cover plate 31 and oil or other fluid is poured into one plugaperture while the other plug aperture acts as an air vent. Theretracted plunger allows the tank 4| to be filled with oil. As shown inFigure 7, a pump assembly 41 is provided in another aperture of the ringblock 35. This pump assembly includes a piston 48 slidably operating inthe bore of a block 49 contained in the aperture and connected to acarrier 59 for a roller 5| adapted to ride on the cam track Ma. Thecarrier 50 is slidably mounted in a sleeve 52 carried by the block 35and projecting therefrom into the space between the block and the backwall 2|b of the hub. A coil spring 53 acts on the carrier 50 to urge itoutward from the sleeve 52 and seat its flange 50a on a shoulder 52aprovided in the sleeve. The cam track Mo on which the roller 5| ridesreciprocates the piston 48 to pump fluid supplied thereto from the tank4| as will be more fully hereinafter described.

As shown in Figures 12 and 13, the ring block space between the blockand the back wall 2 lb of i the hub. As shown in Figure 5, this buttonend 51a of the plunger acts on the pin 30 to rotate the blade B therebychanging the pitch of the blade.

As shown in Figures 7 to 11, a valve assembly 66 is provided in anotheraperture of the block ring 35. This assembly 66 includes a block 6|disposed in the aperture of the ring block 35 and slidably receiving adumbbell type valve 62. The

valve 62 has a stem projecting through the bottom plate 39 of the ringblock and attached to a carrier 63 for a roller 64 adapted to ride onthe track portion MD of the control member l4. A

the block 60 symmetrically around the central dumbbell valve 62 asillustrated in Figures 8 to 11. As shown in Figures 9, 14 and 15, thecover plate 31 has a groove therein providing a passageway 66 to thevalve seat 10 of the first valve assembly. A ball 1| is pressed by aspring 12 to seat against the seat 16. Fluid under pressure of the pumpis sufficient to unseat the ball 1| so that the fluid can flow throughthe passageway 13 into anothmer groove 14 in the cover 31. This groove14 has communication with the seat 15 of the second valve assembly, withthe pump chamber of pump assembly 41, and with the third valve assembly.

As shown, oil can be drawn from tank 4| on the suction stroke of thepiston 48 to flow through check valve 10 into passage 13 and groove 14.Pressured oil can be by-passed from plunger 48 through check valve 16into passages 18 and 19 back to the tank, as hereinafter described. InFigure 15 the passageway 19 is shown diagrammatically as being in thering block whereas, as shown in Figures 10 and 14, this passageway 19 isactually a groove in the cover 31 communicating with groove passageway69. The connected grooves 19 and 59 by-pass the oil from passage 18 backto the tank, while the groove 69 also supplies oil to the pump throughcheck valve 16.

Fluid can also flow from the groove 14 into a passage so to the valveseat 8| of the third valve assembly where it can force the ball 82 offof the seat against the pressure of the spring 83 and then flow into apassageway or groove in the cover. The groove 84 communicates with apassageway 85 in the ring block, which passageway communicates with agroove 86 around the sleeve 56 of the plunger assembly to a passageway81 in the ring block connected through a passageway 88 to the chamber ofthe dumbbell valve. The valve 62 can connect the passageway 88 with apassageway 96 communicating through a groove 9| in the cover plate withthe ends of both plungers to move the plungers against the pins 30 forrotating the blades into low pitch. Alternately, the valve 62 can blockthe passageway 88 and join the groove 9| and passageway 90 with apassageway 92. This passageway 92 in the ring block 35 communicates witha groove 93 around the sleeve 56 of the second plunger assembly 55 andthe groove 93, in turn, communicates with a passageway 94 back to theoil tank.

Operation of the device The propeller pitch-changing device of thisinvention includes a hub assembly rotatably carrying propeller blades toturn about radial axes from high pitch to low pitch positions, thelimits of which are determined by the positions and settings of the setscrews 32. In normal operation, the aerodynamic and other forces on thepropeller blades maintain the blades in high pitch position because theblades are arranged to have their centers of pressure forwardly of theiraxes of radial rotation.

When it is desired to rotate the blades about their axes of radialrotation into low pitch posisleeve slidably receives the carrier 63 andis tion, the pilot merely pulls the Bowden wire or control rod at. Thisrotates the control member M in the mounting plate I0, and rotation ofthe control member throws it axially forward because the bolt heads |6aseat in tapered slots I5.

The control member has an inclined cam track or ramp 4a on its frontface together with a flat surface around this cam track. When theestates eontfol member is moved forwardly "the dam track 14c engages theroller ei of thepuinp assaintly -4"! whilef'the surface Mb around thecam track engages the roller 64 of the valve assembly 60. M g The camtrack M'a reciprocates the plunger #8 'ofthepump and causes-the pump topump oil from the tank 4|, Thus, on the suction shake jg: the pump,oilis drawn in pastthe check v'a1v'e "H and, on the pressnre stroke orthe pump, the thus drawn-m oil is discharged against the check Valve 82.If the pressure is'tdo great, theoil will now past the check valve 56back to the tank.

The oil under pressure flows from the check valve iifiintothedumbbellvalvemperatihg chamberand the engagement of the roller 64 of thevalve with the surface Mb of the control men ber moves the valve to aposition so that the 'oil will flow tothe ends of the plunger-s '55throw- "ing these plungers oiitwa'rdly again'stthe "pins 3'0 and thusrotating the blades B to low pitch positions as determined by thesetting "of the "set LISCIEWS 32.

The pump will continue to operateas long as the "control member is inits forward position and resume their high pitch position, the -Bowdehwire or'control rod 2D is 'againactuatedby the pilot to rotate thecontrol member [4 in the reverse directionwhe'reupon the screw heads [6aand slots 15 retract the'control mei'nberto space the cam track lia'away from the roller The spring 66 of the valve assemb1ymovesth'e'dufnbbell'valve'to place the passages 9| and 'llil in com--munication with the passages-'92 and 94 backto the tank. The aerodynamicand other forces on the blades are thus suffi'cie'nt to rotate theblades ancithe pins 30 will force th'e pIungers-EE back into the ringblock tfi. The oil in back of these 'pIunger's can flow freely throughthe valve back to the tank.

plane engine while the hub 'w'ill replace'the con;-

ventional propeller hub. I

It will, of course, be un'derstoo'dthat various details of constructionmay be varied through Ira wide range without departing fromtheprinciples of this invention and it is,'therefo're,-'not "the purposeto limit the patent'grahted hereon other'wise thannecessitated bythes'cope ofth'e appended claims.

I' claim as my invention:

1. A propeller pitch-adjustin'gdevice comprising a propeller'hu'b hayinga'hollow central portion and radially "extendir'igsockets communicatingwith said central portion, blade-mounting 'devices rotatably carried insaid sockets and having portions projecting into said hollowportion ofthe hub, pins extending laterally in angular "relation from saidprojecting "portions of the blade-mounting devices, set screws threadedin "said hub arrangedto engage opposite sides of "one set of pins onsaid blade mounting devices, hydraulically operate'd "plungersin saidhub a'rrangedto engage thesamesides of the'other set of pins on saidmounting devices for moving said devices to change the pitch of theblades carried therebya pump carried by said hub "for supplyinghydraulic fluid'under-press'ure to said'plungers, a tank carried by saidhub "for supplying hydraulic fluid to'said pump, a control valve carriedby said hub for selectively connecting said plungers with said pump andsaid'tank, anda shift'able cam mounted adjacent said hub having acam-track for actuating saidpump a'nd as'urface for moving said valvewherebyrotatio'n of -the hub andengag'ementof the pump and valve withthe control device will create h-ydraulic'pressii're actuating theplun'gers for changing the -pitch oi the "propeller blades.

2 In an engine including "a shaft, a'pro'pelle'r pitch--'adjustingdevice comprising ahollow hub having radially extending sockets, a ringblock member carried by said 'hub in the hollow interior thereof andarranged tosurround theeng'ine shaft, said block member having aplurality of recesses therein, pl'un'gers slidably mounted in some 'ofsaid recesses, a control valve mounted in another recess, =apump-mountedinstill another "recess, passageways-in said block operativelyconnecting said 'plun'gers, said pump and said control valve for fluidintercommunication, 'said'c'ontrol valve and said pump'havi'ng actuat-{i'ngmea'ns projecting from 'saidblock, propeller 1 blade mountingdevices 'rotatably carried in said 7 sockets and ex'tending in'to thehollow interior 0f the hi-ib arranged to b'e acted "on by said plu'ngerportions, and [ashiftable cam member arranged to be carrie'd byanaircraft engine adjacent said hub and shifted intoen'gage-r'nentwith--said projecting" portions of thepump'and control valve to open thevalve and reciprocate the pump *for supplying fiuid under pressure tosaid plungers to force the plungers outwardly from the ring blockagainst the inwardly projecting portio'ns ofthe blade mounting devicesfor rotating said blade mounting devices.

' JAMES H. BOOTH.

REFERENCES :CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date nei z zss Caldwell Mar. 9,193":Re 21,108 Zipay 'May 30, 1939 Re. 22,034 Hoover Febf24, 1942 1,803,858MacClatc'hie 'May fi, 1931 1,967,461 'Ba'llew July 24,1934 2,0o2;112Patriarche May 28, 1935 2,023,785 Hoover Dec/10,1935 2,032,354 fcaiawen-QFeb. 25,1936 2,075,682 Welman -QMar. 30, 1937 2,229,058 Dicks Jan. 21,1941 12,307,102 Blanchardet' a1. Jan/5,1943 2.347404 Hoover --i -i Apr.18,1944 mesa-939 Augfl, 1944 2,404,290 Hoover *Ju1y'16,' 1946 FO R EIGNPATENTS Number Country Date 1 119,164 AuStra1ia NOV.- 23,1944 601,246France 'Feb. 25,1926 635,992 Germany d. Aug. 30, 1934 782,127 France May28, 1935

